The problems seem to have started at around 8:00 AM this morning and are ongoing at the time this article was posted.
In a further tweet, O2 said the problem was related to a software issue in the system of a third party supplier. In a statement Ericsson told ZDNet: "We are aware of the issue and are working together with our customers to solve it as soon as possible".
The Telegraph confirmed that some customers of these other networks were also affected by the outage. Our priority is to restore full data services on the network by tomorrow morning.
Aside from being a huge inconvenience for data-hungry consumers, the O2 network outage is also causing issues for things such as public transportation and daily operations of local businesses.
"Our technical teams are investigating reports of issues when using data", O2 wrote on its status page.
O2 customers are struggling to access the internet and other services after a massive data failure this morning.
Thousands have taken to social media to vent their frustrations, with services across the country ranging from Transport for London's electronic bus stop timetables to mobile card readers relying on the network. This means that the number of impacted customers is, in reality, likely to be much higher than 25 million.
And while it hasn't been heavily reported, O2 and Softbank are not alone with this issue.
The Sky Help team, responding to customer concerns on Twitter, say the problem has been pinpointed and staff are working with O2 to resolve the situation.
Earlier, O2 said it suspended planned work or updates to its systems and network. "We are really sorry and working as hard and as fast as we can to fix this".